1. Field of the Invention
The present invention relates to a novel substituted N-fluoropyridiniumsulfonate having a lipophilic alkyl or haloalkyl group, intermediates for use in the preparation of said substituted N-fluoropyridiniumsulfonate and processes for preparing said substituted N-fluoropyridiniumsulfonate and said intermediates.
2. Description of the Related Art
For the fluorination of an organic compound, molecular fluorine (F.sub.2) is known and used. Since a reaction between the molecular fluorine and the organic compound proceeds vigorously different from reactions with chlorine, bromine or iodine, its control is very difficult. Therefore, a development of a mild fluorinating agent which can be used in place of the molecular fluorine is one of important subjects in the industry.
As mild fluorinating agents which can be used in place of the molecular fluorine, following compounds have been developed:
acetyl hypofluorite (J. Org. Chem., 48, 724 (1983)); 1-fluoro-2-pyridone (J. Org. Chem., 48, 761 (1983)); cesium fluorooxysulfate (Tetrahedron, 40, 189 (1984)); N-fluoro-N-alkyltoluenesulfonamide (J. Am. Chem. Soc., 106, 452 (1984)); halogen monofluoride (J. Org. Chem., 51, 222 (1986)); N-fluoropyridinium salts (Tetrahedron Lett., 27, 4465 (1986), J. Am. Chem. Soc., 112, 8563 (1990), Bull. Chem. Soc. Jpn., 64, 1081 (1991), Japanese Patent Publication No. 33707/1990, Japanese Patent Kokai Publication Nos. 99062/1991 and 275859/1989, EP-A-393 462 and U.S. Pat. Nos. 4,996,320 and 4,935,519); N-fluoroquinuclidinium salts (J. Chem. Soc., Perkin Trans. I, 1988, 2805); N-fluorosaltum derivatives (Tetrahedron Lett., 29 6087 (1988)); N-fluoro-N,N-bis(trifluoromethanesulfonyl)amide (J. Chem. Soc., Chem. Commun., 1991, 179); N-fluoro-3,3-dimethyl-2,3-dihydro-1,2-benzenethiazole-1,1-dioxide (Helv. Chim. Act., 72, 1248 (1989)); N-fluoro-N-(pentafluoropyridyl)trifluoromethanesulfonamide (J. Fluorine Chem., 46, 297 (1990)); N-fluorolactam (J. Org. Chem., 55, 3373 (1990)); N-fluoro-N,N-bis(benzenesulfonyl)amide (Synlett, 1991, 187); N-fluoro-o-benzenedisulfonimide (Tetrahedron Lett., 32, 1631 (1991)); N-fluoroperfluoropiperidine (J. Fluorine Chem., 52, 389 (1991)); methyl hypofluorite (J. Am. Chem. Soc., 113, 2648 (1991)); and N-alkyl-N'-fluorotriethylenediammonium salts (J. Fluorine Chem., 54, 208 (1991)).
However, the above known fluorinating agents have some drawbacks in efficiency of fluorination, reaction selectivities, stability, handling properties, yields, reaction conditions, or regeneration efficiency of the fluorinating agents, and they do not satisfy the requirements of the industry. The regeneration of the fluorinating agent is a very important matter in view of economy and environmental pollution in the practical application of the fluorinating agent in the industry.